store: Fixed more download issues when some folders don't have write perms

lib/libimhex/include/hex/helpers/file.hpp

@@ -56,7 +56,7 @@ namespace hex {
         void setSize(u64 size);
 
         void flush();
-        void remove();
+        bool remove();
 
         auto getHandle() { return this->m_file; }
         const fs::path &getPath() { return this->m_path; }

lib/libimhex/include/hex/helpers/utils.hpp

@@ -44,6 +44,7 @@ namespace hex {
     std::string encodeByteString(const std::vector<u8> &bytes);
     std::vector<u8> decodeByteString(const std::string &string);
 
+    bool isPathWritable(fs::path path);
 
     [[nodiscard]] constexpr inline u64 extract(u8 from, u8 to, const hex::unsigned_integral auto &value) {
         if (from < to) std::swap(from, to);

lib/libimhex/source/helpers/file.cpp

@@ -122,9 +122,9 @@ namespace hex {
         fflush(this->m_file);
     }
 
-    void File::remove() {
+    bool File::remove() {
         this->close();
-        std::remove(this->m_path.string().c_str());
+        return std::remove(this->m_path.string().c_str()) == 0;
     }
 
 }

lib/libimhex/source/helpers/utils.cpp

@@ -23,6 +23,7 @@
 #endif
 
 #include <hex/helpers/logger.hpp>
+#include <hex/helpers/file.hpp>
 
 namespace hex {
 
@@ -393,6 +394,23 @@ namespace hex {
         return result;
     }
 
+    bool isPathWritable(fs::path path) {
+        constexpr static auto TestFileName = "__imhex__tmp__";
+        {
+            File file(path / TestFileName, File::Mode::Read);
+            if (file.isValid()) {
+                if (!file.remove())
+                    return false;
+            }
+        }
+
+        File file(path / TestFileName, File::Mode::Create);
+        bool result = file.isValid();
+        if (!file.remove())
+            return false;
+
+        return result;
+    }
 
     bool openFileBrowser(const std::string &title, DialogMode mode, const std::vector<nfdfilteritem_t> &validExtensions, const std::function<void(fs::path)> &callback, const std::string &defaultPath) {
         NFD::Init();